TUESDAY, May 2, 2017 (HealthDay News) -- The quality of your relationships with your adult children and spouse might influence your chances of developing dementia, new research suggests.

While having supportive adult children appeared to be protective, having unsupportive relatives of all ilk seemed to have an opposite -- and more dramatic -- effect, the British scientists reported.

The finding "suggests older adults who experienced a reliable, approachable and understanding relationship with their adult children were less likely to develop dementia," said study author Mizanur Khondoker. "Conversely, a close relationship that did not work well -- such as experiencing critical, unreliable and irritating behaviors from spouses or partners, children and other immediate family -- was related to increased risk of developing dementia."

Khondoker is a senior lecturer in medical statistics at Norwich Medical School at the University of East Anglia in Norwich.

To examine how family support might affect dementia risk, the researchers looked at data that had been collected between 2002 and 2012 that included more than 10,000 men and women aged 50 and older. All were deemed dementia-free when they enrolled in the study.

The participants completed questionnaires in which they detailed the social support they had been receiving, or lacking, from at least one key relationship. Such relationships could involve children, spouses, friends, and/or close relatives such as cousins, siblings, parents, and/or grandchildren.

Follow-up interviews were conducted on a bi-annual basis, during which time the researchers recorded all new cases of dementia and ranked social relationships on a negative-to-positive scale ranging from one to four.

By the end of the study, 3.4 percent of the participants (190 men and 150 women) had developed some form of dementia.

The researchers observed that those who had received positive support from their adult children faced a reduced risk of dementia. Khondoker described the association as "modest," noting that for every one-point increase in positive support from an adult child, dementia risk dropped by an average of 17 percent.

Conversely, for every one-point increase in an individual's overall negative social support "score" -- the risk for dementia went up by 31 percent, he said.

Khondoker said the study simply assessed the overall risk that someone would develop dementia of any kind, and did not differentiate dementia by type. Also, the research wasn't designed to prove a cause-and-effect relationship between family support and dementia risk.

But the research team theorized that social support may promote healthy behaviors, such as minimal drinking and an active lifestyle. On the other hand, a negative close relationship might discourage such positive choices, while also giving rise to increased stress.

"Further research is needed to better understand any causal mechanisms that explain the statistical associations observed," Khondoker added.

The findings were published May 2 in the Journal of Alzheimer's Disease.

Dr. Anton Porsteinsson directs the Alzheimer's Disease Care, Research and Education Program at the University of Rochester School of Medicine and Dentistry in New York. He said the study "raises many questions."

For example, he noted that the link between negative relationships and dementia risk appeared to be much stronger than the link between positive relationships and dementia risk.

But why? "If your relationships with those around you are predominantly negative we may assume that there is less social interaction and cognitive stimulation that may lead to worse outcome," said Porsteinsson. "It may also be that those that have a less healthy lifestyle are involved in negative relationships overall, and thus [exposed to] more stress, which combined together is likely to be harmful."

Also, behavioral changes caused by the unsuspected onset of dementia may undermine relationships, making it difficult to know which is the chicken and which is the egg, he said.

"Understanding whether relationships are causal factors or a consequence is the next step of inquiry here," Porsteinsson said.